A grasshopper can jump a maximum distance 1.6 m. It spends negligible time on the ground. How far can it go in 10 s?

Here angle of projection = 45°
$$\begin{gathered} {\mathrm{R}}_{max}=1.6=\frac{{\mathrm{u}}^2}{\mathrm{g}}=\frac{{\mathrm{u}}^2}{10}\text{ or }\mathrm{u}=4{\mathrm{ms}}^{-1} \\ \mathrm{Hence}, \mathrm{the} \mathrm{distance} \mathrm{covered} \mathrm{in} 10 \mathrm{s} \mathrm{is} \mathrm{horizontal} \mathrm{speed} \mathrm{x} \mathrm{time} = \mathrm{u} \cos 45° \times \mathrm{time} \\ =4\times \frac{1}{\sqrt{2}}\times 10=20\sqrt{2}\mathrm{m}\mid \end{gathered}$$